Atopic dermatitis is a disorder of the upper layers of the skin that usually begins in childhood. It typically affects those in families with a history of atopic dermatitis, allergic conditions or asthma. Scaly, itchy skin rashes are typical symptoms of the disorder, which is the most severe and longest-lasting form of dermatitis.

Atopic conditions occur in people who are overly sensitive to allergens in their environment. Though not technically caused by allergies, and not always triggered by an allergen, atopic dermatitis usually appears in infants and young children who already have allergies, or who are likely to develop them later.

The pattern of rash distribution is a distinguishing feature of atopic dermatitis, which is a common type of eczema (an inflammatory skin disease). Red, itchy patches usually start on the face, particularly the cheeks and chin. Over time, the face heals, but for some the rash will then appear on other parts of the body.